Manufacture of gold leaf



Oct. 21, 1924. 1,512,825

F. DEMEL MANUFACTURE OF GOLD LEAF Filed Oct. 29. 1923 that a. r, 1924.,

we? D OF TWIGKENHAM, ENGLAND, ASSIGNOR OF ONE-HALF TO TINDALI: LFJGHTO'N, OF HOVE, SUSSEX, ENGLAND.

UFACTURE OF GOLD LEAF.

Application filed October 29, 1923. Seriall No. 671,551.

To all whom it may concern:

Be it known that I, FRIEDRICH DEMEL, a subject of the King of Great Britain, residing at Twickenham, England, have invent- 6 ed certain new and useful Improved Manufacture of Gold Leaf, of which the followin is a specification.

y invention relates to the electrolytic manufacture of gold leaf. Such manufacm ture has already been proposed, one prof posed method consisting in depositing the gold electrolytically on one face of a strip or band of a base metal forming the cathode of an electrolytic cell which contains a solution of a composition suitable for the electro-deposition of gold, either in the pure state or alloyed with any of the metals which usually enter into the composition of gold leaf, the base metal being then dissolved away, for instance, by nitric acid, and the old film which remains being washed and ied. Such processes have not, however, been applied industrially because of the fact that the old leaf cannot be removed from water an dried in a manner which permits of its subsequent manipulation.

My invention consists in displacing the water remaining on the gold leaf by means of a volatile solvent for water, for example at by alcohol or methylated spirits, before the drying operation, whereby it becomes possible to dry the leaf in such a ,manner that it can be brought between paper sheets or leaves in the usual way.

For this purpose, after the base metal, on one side of which the film ofsgold has been deposited, has been dissolved, for example by treatment with nitric acid, the gold leaf which remains is brought into contact suc- ,4} cmsively with water (which may be slightly alkaline, preferably by the addition of ammonia, to remove free acid), and then with alcohol or other volatile solvent for water, after which it may be brought onto a plate at of suitable material, for instance carbon, and dried. It may then be manipulated with force s. I

One met 0d of carrying out the invention is illustrated in the accompanying diagramto maticdrawing which represents in Fig. 1 in verticai section the apparatus for removing the silver from the electrodeposited gold and drying the latter to produce gold leaf. Fig.

2 shows a detail. The drum a carrying the gilded silver band is mounted on axle 6 shown in a position for the unrolling of the band with the gilt surface uppermost. The apparatus comprises an endless band 0 of suitable material, such as celluloid, which travels over a number of guide rollers (Z, one or more of which are suitably driven. One of these rollers, 03, is submerged in a bath of dilute nitric acid 6, another,d in a bath of water and a third, (P, in a bath containing methylated spirit 9. The nitric acid may be of per cent strength and the methylated spirit "of 90 per cent strength. The Water may be kept slightly alkaline with ammonia to neutralize the acid adhering to the film.

The silver band having been laid upon the endless band 0 is unwound by the movement of the latter. At the point Where the band 0 enters the nitric acid the silver band leaves it and continues to travel on the surface of the nitric acid'which dissolves the silver leaving only the film of gold to be taken up again by the band 0 at the point where the latter leaves the acid. In like manner the film of gold travels along the surface of the water f, where it is washed and finally leaves the band 0 to pass on to the surface of the methylated spirit in the pocket 9 where most of the water is removed from it by this portion of the methylated spirit, the remainder of the water being removed by the main body of the spirit before the goldis taken up by the endless chain of plates h. The latter are made of carbon, for instance by.carbonizing coal briquetted to the required shape. Each plate carries a toothed rackz' (Fig. 2) and these racks are connected by links k constituting the chain. The plates are carried by pentagonal drums Z and the chain is driven by four pinions m themselves driven by suitable mechanism (not shown). The lower drum Z is submerged in the spirit. The upper run of the chain passes over an open box at in which 100 suction is created by a fan (not shown) for the purpose of causing most of the spirit to evaporate, and then over an electric heater 0. The hot air fromthe heater lifts the film from the carbon, thus permitting it to 1 be caught by forceps, and laid between paper bands which are being wound on a roller.

It is to be noted that it is not essential that the base metal band should be continuone during the process of dissolving the metal. If, for instance, the silver band he cut transversely at intervals as it passes over the first guide roller 03, the successive rectangles will follow each other throughout 5 the apparatus and separate sheets of the gold film will finally be removed by forceps from the carbonplates h.

It is to be understood that the invention is not limited in its application to the particular method described and illustrated in the drawing.

Having thus fully described the nature of the said invention and the best means I know of carrying the same into practical effect, I claim 1. An electrolytic manufacture of gold leaf which consists in depositing gold electrolytically on one face of a band of base metal, dissolving the base metal by means of an acid, Washing the remaining gold film by bringing it into contact with water, and dislacing water from the film by bringing the film into contact with a volatile solvent for Water.

2. An electrolytic manufacture of gold leaf which consists in depositing gold electrolytically on one face of a band of base metal, dissolvin the base metal by means of an acid, washing the remaining gold film by bringing it into contact with water, and displacing water from the film by bringing the film into contact with alcohol.

3. An electrolytic manufacture of gold leaf which consists in depositing gold electrolytically on one face of a band of base metal, dissolving the base metal by means of an acid, washing the remaining gold film by bringing it into contact with water, removing said film from the Water, and then displacing water adhering to the film by bringing it into contact with a volatile solvent for water.

4. An electrolytic manufacture of gold leaf which consists indepositing old electrolytically on one face of a ban of base metal, dissolving the base metal by means of an acid, washing the remaining gold film by bringing it into contact with water, removing said film from the water, and then displacing water adhering to the film by bringing 1t into contact with alcohol.

5. An electrolytic manufacture of gold leaf which consists in depositing gold electrolytically on one face of a band of base metal, dissolving the base metal by means of an acid, washing the remaining gold film by bringing it into contact with water, re-

moving said film from the water, displacing water adhering to the film by bringing it into contact with a volatile solvent for water, and finally removing said film from said solvent and drying it.

6. An electrolytic manufacture of gold leaf which consists in depositing old electrolytically on one face of a ban of base metal, dissolving the base metal by means of an acid, washing the remaining gold film by bringing it into contact with water, removing said film from the water, displacing Water adhering to the film by bringing it into contact with alcohol, and finally removing said film from the alcohol and drying it.

7. Apparatus for the electrolytic manufacture of gold leaf comprising a. strip of base metal, means for electrolytically depositing the gold on one face of said strip, an acid-conta ning vat, a water-containing vat, an alcohol-containing vat, and means for bringing said strip into contact successively with the acid, water and alcohol contained in said vats.

8. Apparatus for the electrolytic manufacture of gold leaf, comprising means for electrolytically depositing gold on one face of a strip of base metal, an acid-containing vat, a water-containing vat, an alcohol containing vat, means for bringing said stri into contact successively with the aci water and alcohol contained in said vats, a

carbon plate, means for depositing the film of gold remaining after treatment in said vats upon said carbon plate, and means for heating said plate.

9. Apparatus for the electrolytic 'manu facture' of gold leaf, comprising means for electrolytically depositing gold upon one face of a strip of base metal, an acid-containing vat, a water-containing vat, and an alcohol containing vat, an endless band travelling through said vats in succession in the order named, an endless travelling chain of carbon plates, a heater over which said chain passes, means for feeding a strip of base metal upon said band before it enters said acid-containing vat, and means for causing the gold film left upon said band when said band emerges from the acid-containing vat to leave said band and to pass upon said chain when said film comes 1nto contact with the alcohol contained in said alcohol-containing vat.

In testimony whereof I have signed my name to this specification.

FRIEDRICH DEMEL. 

